In our past work using stationary eye tracking, we have shown that older adults with good attentional abilities can successfully use attentional deployment to regulate their moods in real- time. More recently, we have investigated situation selection as a distinct emotion regulation strategy by creating a choice-laden Affective Environment in which participants of different ages make choices among emotional stimuli as they might do in their everyday lives. The current proposal uses mobile eye tracking in the Affective Environment in order to combine the study of attentional deployment with situation selection. The project will investigate how younger, middle-aged, and older adults dynamically use both situation selection and attentional deployment in real-time to regulate how they feel. This work is developmental and exploratory; no previous work has used mobile eye tracking to study emotion regulation. Doing so requires tackling a serious data processing limitation. Every participant's environment is idiosyncratic as a function of their choices, rendering their visual fixation data hard to interpret using currently available software systems. To solve this problem, psychologists working on mobile eye tracking will partner with computer scientists working in game design to create a custom program for associating fixations with selected stimuli, permitting more automated processing and analysis of data. Two studies will be conducted with younger, middle-aged, and older adults: in both, participants will spend time in the Affective Environment after a mood induction (negative mood in Study 1, positive mood in Study 2) and will be instructed to either regulate to the best possible mood state, or to interact naturally wit the environment. Choices and fixations will be recorded with mobile eye tracking and our newly-created software, and mood will be recorded in real-time. Analyses will test the extent to which there are age differences in choices and fixations, as well as how these choices and fixations predict real-time mood regulation. In addition to testing the interplay of situation selection and attentional deployment in real-time ambulatory emotion regulation, this project will yield a method and software that can be used by other labs to study dynamic fixation and emotion regulation across the lifespan.